The general-purpose rifle
Deer, hogs, black bear, most elk. Enough magnification for a careful 300-yard shot, enough field of view for 40 yards in timber, and light enough not to change how the rifle handles.
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Riflescopes
Magnification, objective size, reticle, turrets and focal plane — what each number does in the field, and which combination actually suits the rifle you own.
Decode the model name
What 3–9×40 actually tells you
Every scope name is two numbers joined by a multiplication sign, then a third. The first pair is the magnification range, the last is the objective lens diameter in millimetres. A 3–9×40 adjusts between three and nine times life size, through a 40 mm front lens. A fixed 4×32 does not adjust at all.
Those three numbers determine field of view, brightness, weight, how high the scope sits over the bore, and how forgiving the scope is when you throw the rifle up in a hurry. Almost every buying mistake traces back to reading them wrong.
Magnification: less than you think
Magnification multiplies the target and everything else. At 4× a heartbeat is invisible; at 16× the reticle swims. It also cuts field of view hard, and field of view is what lets you find a moving animal before it is gone.
| Power | Realistic use | Field of view at 100 yd | Watch out for |
|---|---|---|---|
| 1–4× | Brush, dangerous game, driven hunts | Roughly 25–100 ft | Hard to place a precise shot past 200 yd |
| 2–7× | Timber whitetail, slug guns, youth rifles | Roughly 15–45 ft | Tops out for open country |
| 3–9× | The all-round default for big game | Roughly 12–35 ft | Almost nothing — this is why it sells |
| 4–12× | Open country, coyotes, target work | Roughly 9–27 ft | Dim at top power in poor light |
| 6–18× and up | Varmints, benchrest, known-distance | Under 18 ft | Mirage, wobble, heavy, needs parallax adjustment |
Field test
Set your scope to its highest power and try to find a fence post 150 yards away from a standing position, in ten seconds, without using the barrel as a pointer. If you cannot, that magnification is not your hunting setting — it is your inspection setting.
Objective size and exit pupil
The objective gathers light, but your eye can only use a cone of it called the exit pupil: objective diameter divided by magnification. A dark-adapted adult pupil opens to about 5–7 mm when young and noticeably less with age, so an exit pupil larger than roughly 5 mm is wasted.
| Scope | Exit pupil at low power | Exit pupil at top power | Practical read |
|---|---|---|---|
| 3–9×40 | 13.3 mm | 4.4 mm | Comfortable to the last legal minute |
| 4–12×40 | 10.0 mm | 3.3 mm | Dial back to 8× at dusk |
| 3–9×50 | 16.7 mm | 5.6 mm | Marginal gain, needs taller rings |
| 6–18×44 | 7.3 mm | 2.4 mm | Daylight and bench work only |
Note what the 50 mm objective costs: taller rings, a higher line of sight, a worse cheek weld and more weight, in exchange for about a millimetre of exit pupil most eyes cannot use. Coatings and glass quality do more for low-light performance than diameter does.
Reticles
The reticle is the part you will actually be looking at under pressure, so pick for legibility first and cleverness second.
| Reticle | How it works | Best for |
|---|---|---|
| Duplex | Thick outer posts taper to a fine centre cross | Almost all hunting. Draws the eye to centre in bad light |
| BDC / holdover | Stacked dots or bars below centre for extra distance | Open country, once you have verified each mark with your own load |
| Mil-dot | Evenly spaced dots for ranging and wind holds | Known-distance and tactical work, if you know the maths |
| Fine crosshair | Thin wires, no posts | Bench and varmint shooting on light backgrounds |
| Illuminated | Battery-lit centre element | Dark timber and low contrast, provided you can dim it enough |
About BDC marks
Bullet drop compensating reticles are calibrated to one assumed velocity, bullet and atmosphere. Yours will differ. Treat the marks as a starting point, then confirm every single one on paper at the actual distance before you trust it on an animal.
Turrets and adjustment
Most hunting scopes use quarter-MOA clicks: one click moves impact about a quarter inch at 100 yards, half an inch at 200, and so on. Capped turrets stay where you left them and are the right choice if you zero once and hold over. Exposed target turrets are for shooters who dial for every shot and are willing to count clicks back to zero afterwards.
What matters more than the click value is whether the adjustments track: dial twelve clicks up, twelve right, twelve down, twelve left and you should land back in the same hole. This is the classic box test, and it is the single most useful thing you can do with a new scope.
First and second focal plane
In a second focal plane scope (SFP), the reticle stays the same visual size while the image grows, so any holdover mark is only correct at one stated magnification — usually maximum. In a first focal plane scope (FFP), the reticle grows with the image, so subtensions are correct at every power, at the cost of a reticle that can be hairline-thin at low magnification. For general hunting inside 400 yards, SFP is easier to live with.
Parallax
Parallax is the reticle appearing to shift against the target when your eye moves off the optical axis. Most hunting scopes are factory-set parallax-free at 100 or 150 yards, which is fine. Rimfire scopes are usually set at 50 yards, and high-magnification scopes add a side focus or adjustable objective so you can correct it by distance. If you shoot a centrefire scope on a rimfire at 25 yards, expect visible parallax.
By intended use
Sensible starting points
Configurations that have earned their reputation, described generically so they stay useful whichever brand or era you end up buying.
Open country and predators
Prairie, plains and coyote stands where the shot is measured rather than snapped. Give up some low-light performance at top power in exchange for reach.
Check listingsTimber and slug guns
Short, light, wide at the bottom end and very forgiving of a fast mount. The right answer for thick cover and for recoil-heavy shotguns where eye relief matters.
Check listingsRimfire
Nothing to fiddle with, correct parallax for the distance you actually shoot, and cheap enough that the scope does not cost more than the rifle. Still the best value in optics.
Check listingsVarmint and bench
Adjustable parallax, target turrets, fine reticle. Heavy and dim at the top end, which is fine because you will be shooting it from a rest in daylight.
Check listingsClose and fast
Effectively a red dot at the bottom of the range with enough magnification at the top for a deliberate 200-yard shot. Popular on straight-wall and lever guns.
Check listingsCommon questions
Riflescope FAQ
How much should I spend on the scope versus the rifle?
The old advice was to spend as much on glass as on the rifle, and it still holds better than most gun-shop wisdom. A modest rifle with good glass and good rings will outshoot an expensive rifle with a scope that will not hold zero. If your total budget is tight, buy less rifle before you buy less scope, and never economise on rings.
Do I need a 30 mm tube?
Only if you need the extra internal adjustment range it provides, which is typically a long-range concern. A 30 mm tube does not by itself make a scope brighter — brightness comes from the lenses and coatings. It does mean you need 30 mm rings, so check before you buy.
My scope will not zero — I have run out of adjustment.
Nearly always a mounting problem rather than a scope fault. Check that the bases are the correct pattern for your receiver, that the rear base is not reversed, and that nothing is bent. A tapered or shimmed base gives back elevation. Running a scope near the end of its adjustment range also degrades the image and repeatability, so fix the mount rather than living with it.
What is the box test and why does it matter?
Fire a group, then dial a fixed number of clicks up, fire, right, fire, down, fire, and left, fire. You should shoot a square and the last group should land on top of the first. It proves the turrets move the reticle the amount they claim and return to zero. Do it once when the scope is new; it takes twenty rounds and tells you whether you can trust the adjustments.
Should I get an illuminated reticle?
Useful in dark timber against a black animal, and useless if the lowest brightness setting still blooms and blots out the target. If you buy illuminated, check that it dims far enough to be a faint glow rather than a lamp, and carry a spare battery.
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